also: しいちろくじけん
noun
April 16 Incident
Historical term for the mass arrest of communists and anti-government activists in Japan on April 16, 1929.
四・一六事件は、1929年に日本で共産党員らが一斉検挙された事件です。
The April 16 Incident was a mass arrest of Communist Party members and others in Japan in 1929.
The March 15 Incident of 1928, a similar mass arrest of communists and leftists that preceded the April 16 Incident.
Named after the date of the incident: April 16 (四・一六). The reading よんいちろく is the standard on'yomi for the numbers, while しいちろく is an alternate reading.